Present invention is directed to a cable clamp device of the type in which a spring-driven wedge or pawl mounted within the device acts to permit movement of the cable in a first direction but clamps the cable against movement in an opposite direction.
The patent literature is replete with cable clamp devices comprised of housings having one or more through-going passages. In these devices, a wedge member is spring-urged towards an inclined wall within the passage. A cable interposed between the inclined wall and the spring-pressed pawl or wedge is free to move in a direction which would tend to increase the spacing between the wedge and the inclined wall portion. Attempted movement of the cable in a direction tending to urge the wedge toward the inclined wall results in the cable being securely clamped between the wedge and inclination.
Representative examples of clamp devices operating on the above-described principle are as follows: U.S. Pat. Nos. 5,147,145; 6,003,210; 6,058,574; 4,935,993; 4,266,756; 4,216,568; 4,129,927; 2,983,012; 3,927,3441; 2,387,436; 1,811,942; 1,271,912; 1,139,595; 1,139,515; and 15,290.
While the above-referenced patents provide a variety of means for effectively clamping cables within a housing or clamping a pair of cables against each other, a problem has existed in respect of releasing a clamped cable from a clamp device. More particularly, it has been observed that a cable component which has been clamped over extended periods, or a cable clamped under high tensile forces involves a difficult problem to effect release of the clamped cable. In some instances, the pawl or wedge becomes embedded into the clamped cable with consequent deformation of the cable rendering retraction of the wedge to a cable release position extremely difficult.
Certain of the prior art references cited above incorporate attempts to solve the cable release problem. By way of example 6,058,574 incorporates a rod having a hook-like internal portion which engages an undercut in the pawl mechanism whereby the pawl may be retracted by pulling on the rod. Such a solution may be effective where only limited forces are necessary to retract the wedge. Moreover, the device of the subject patent involves providing them with complex machined elements which are difficult to assemble.
The present invention is directed to an improved cable clamp device characterized in that the housing for the clamp may comprise a simple casting and assembly of the clamp components to the casting is easily accomplished. The invention is further directed to a cable clamp of the spring-driven wedge type wherein release of a clamped cable may be readily effected with the use of a simple tool such as a pair of pliers.
Still more particularly, the invention is directed to a cable clamp having a through-passage for a cable, a wedge and a spring within the passage, the spring pressing the wedge toward a clamp surface within the housing. A characterizing feature of the invention resides in the provision of a slot in the housing which communicates with the passage. A spring has a first end biased against an abutment at the end of the passage, the opposite side of the spring bearing against the wedge. Assembly of the components is effected by the simple process of passing a retraction pin through the slot in the housing and into a blind bore formed in the wedge. It will thus be appreciated that the simple process of inserting a pin through the slot and press fitting the pin into a blind bore in the wedge completes the assembly process. It will further be appreciated that release of a cable may be readily effected by engaging one jaw of the pliers with the projecting pin and the other jaw with an external portion of the housing, whereby a compressive force sufficient to release the clamped cable may be readily applied. The projection or pin while movable in the slot prevents disassembly of the parts by the engagement of the pin against a limit or end portion of the slot.
It is accordingly an object of the invention to provide a cable clamp incorporating a minimum number of components parts which are susceptible of easy assembly. A further object of the invention resides in providing a clamp of the type described wherein release of the clamped cable may be readily effected notwithstanding the cable has been clamped for protracted periods and/or has been subjected to high tensioning forces on the cable which tend to distort the cable component.
Still other and further objects will appear herein or be hereinafter pointed out in the course of the detailed description of the device.